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对大别山南部超高压带内金河桥榴辉岩的金红石和绿辉石进行了U-Pb同位素分析, 利用等时线法和依据绿辉石Pb同位素组成扣除普通Pb法获得了一致的高精度金红石U-Pb年龄(218±1.2) Ma. 这表明低μ的绿辉石可以作为金红石普通Pb扣除的依据. 另外, 根据前人研究结果计算得到在快速冷却条件下金红石U-Pb体系封闭温度为(470±50)℃. 这一结果证明218 Ma代表超高压岩石冷却到470℃左右的时间, 而非峰期变质时代. 它证明大别山南部超高压岩石在峰期变质之后经历了一次快速冷却过程.
U-Pb isotopic analyzes of the rutile and omphacite of the Jinheqiao eclogite in the UHP belt in the southern part of the Dabie Mountains were carried out using the isochron method and deduced from the Pb isotope composition of omphacite to obtain a uniform high The accuracy of the rutile U-Pb age (218 ± 1.2) Ma. This shows that the low μ omit can be used as rutile normal Pb deduction basis. In addition, based on previous research results obtained under the conditions of rapid cooling rutile U-Pb system closed (470 ± 50) ℃ .This result proves that 218 Ma stands for the ultra-high pressure rock cooling to about 470 ℃, rather than the peak metamorphic age.It proves that the ultrahigh-pressure rock in the southern part of the Dabie Mountains experienced a rapid deterioration after the peak period Cooling process.